I have been searching for years to find a great and easy to use visual prototyping tool with no success. First I tried out Origami from the team at Facebook (read previous article) that sat on Apple’s free Quartz Composer application that had traditionally been used as a motion graphics tool but found it to be too complicated to use in a real workflow. Then I tried Avocado from the team at IDEO (read previous article) that looked to try to improve upon the work that had been done in Origami but here again the application was just too complicated and the learning curve was too high to make it a realistic option for my work. Finally there was Form from Relative Wave (read previous article) which got my attention because it had a desktop app to create the prototypes and an iOS companion app that will let you run your prototypes on actual devices. It had the same node based interface from Quartz Composer, Origami and Avocado and even though it was a little simpler to use it still wasn’t what I was looking for. I wanted an application that was simple to use but powerful enough to allow me to create new and complex interfaces that give me subtle control over interactions and animation.
A few weeks ago I came across a new app called Principle from former Apple Engineer Daniel Hooper that looked promising but I was skeptical and didn’t want to get my hopes up that this might finally be the tool I has been looking for after so many disappointments. The app costs $99 but thankfully they had a free 14 day trial that let me take the app for a test drive. When I launched the app I noticed that the interface felt instantly familiar with the same UI aesthetic as Sketch and Apple’s applications like Keynote that look simple at first but you quickly find contain powerful tools. The similarities with Sketch continued as I found that Principle had an inspector, layers list, mirror functionality and best of all – my beloved artboards. These things alone put it MILES ahead of any other visual prototyping app I had tried but I wanted to put it through its paces to be sure.
Just like with Sketch I found that within an hour I was flying through the programming creating what I wanted which was nothing short of AMAZING! Each screen of your prototype is put into a new dartboard and you import your assets from another application to give you all the elements you need. You then add interactions like tap, long press, scrolling, dragging or touch that you choose from a menu and drag from the trigger element to the resulting destination. A floating prototyping window then lets you instantly test out the results to make sure it is the action you wanted. But then I saw something that had me dancing around my studio – an animation panel. Similar to what you would find in an application like After Effects where you can control the duration and even customize the animation curves to get the exact feel you want. There is also functionality called Drivers which are a little more complicated to understand but they basically allow you to create sophisticated continuous interactions that are more complex and customizable than a simple animation.
Principle is still in its early days but the functionality and promise of this application is far and away the best I’ve ever seen. If you are doing any digital design work you really need to try this app because I think Principle could do for prototyping what Sketch recently did for design. You can find out more about the app here, watch tutorials on how to use the app here, review the documentation here and follow them on Twitter here.